1. Field of the Invention
The present invention relates to a motorcycle, and more particularly to a motorcycle provided with a duct through which air is led to a belt chamber.
2. Description of Related Art
Some motorcycle transmissions use a V-belt, which is simple in construction and inexpensive. Since a V-belt may slip when dust and sludge adhere thereto, the V-belt is accommodated in a belt chamber to prevent adherence of dust, sludge, etc. thereto. However, the V-belt generates heat due to friction with a drive pulley at the time of running, which decreases the V-belt in durability. And, when the V-belt is accommodated in a belt chamber, heat works, so that the V-belt is increased in temperature even more.
In order to solve the problem, cooling devices are known that introduce outside air into a belt chamber to decrease temperature in the belt chamber. For example, JP-A-10-218062 and JP-A-2000-79892 disclose such cooling devices.
JP-A-10-218062 provides a clean room below a low foot put base arranged forwardly of a belt chamber, and an outside-air intake port of an intake duct is formed in the clean room. However, since the outside-air intake port is arranged in a low position of the vehicle body and in the vicinity of a front wheel, the internal construction of the clean room must be complex in order to prevent invasion of dust that is splashed by the front wheel.
JP-A-2000-79892 provides a transmission case bearing a V-belt wrapping mechanism and an air cleaner arranged above the transmission case to purify outside air. The outside air for cooling the transmission case is introduced from the air cleaner. However, since the outside-air intake port of the air cleaner is arranged just above a rear wheel, dust splashed by the rear wheel is mixed with the air sucked into the intake port, making it necessary to frequently perform maintenance of the air cleaner.
Thus, in the related art, the peripheral construction of the intake duct must be complex in order to prevent dust and sludge splashed by front and rear wheels from entering the belt chamber, or to be able to take in outside air through the air cleaner without the requirement of frequent cleaning.